Dishwasher

ABSTRACT

The present invention relates to a dishwasher. The dishwasher of the present invention may include a sump for holding cleaning water, a cleaning pump for pumping the cleaning water from the sump, a spray arm for spraying the cleaning water through two or more nozzles, a supply flow passage for forming a flow passage to supply the cleaning water pumped by the cleaning pump to the spray arm, and an air mixing unit for drawing external air to spray the cleaning water through the nozzles together with the air. The air mixing unit may be mounted between the nozzle which sprays the cleaning water and an inlet of the supply flow passage connected to the spray arm, or the end of the supply flow passage connected to the spray arm. Accordingly, the washability of the dishwasher can be improved without increasing the amount of water used.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119 to Korean Application No. 10-2012-0100401 filed on Sep. 11, 2012, whose entire disclosure is hereby incorporated by reference.

BACKGROUND

1. Field

The present invention relates to a dishwasher. More specifically, the present invention relates to a dishwasher which increases a spray pressure of cleaning water without increasing an amount of the water used.

2. Related Art

The dishwasher is a machine for spraying cleaning water including detergent at a high pressure to tableware (Including dishes and cooking tools) for cleaning by washing dirt from the tableware, rinsing the tableware, and removing moisture from a surface of the tableware to dry the same.

A washability of the dishwasher which is a capability for cleaning the dirt from the tableware may vary with a temperature of the cleaning water, hitting power which is power the cleaning water hits the tableware, an amount of the cleaning water used for washing.

Since a method of increasing the temperature of the cleaning water for increasing the washability is an action against a trend of energy saving as the method require more heating energy, and a method of increasing the amount of the water used is also opposite to policies on environment and energy, it is not appropriate to take such methods into account as methods for increasing the washability.

The hitting power corresponds to the spray pressure that is a water pressure from a nozzle that ejects the cleaning water, wherein as a method for increasing the spray pressure, though increasing a rotation speed of a motor for increasing the amount of the cleaning water used or circulating the cleaning water may be considered easily, those are also opposite to the policies on energy and environment.

Consequently, as a method for enhancing the washability, a method is required, in which the spray pressure is increased without increasing the rotation speed of the motor for circulating the cleaning water, or without increasing the amount of the cleaning water used.

The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.

SUMMARY

Accordingly, the present invention has been made in an effort to solve the aforementioned problems, and it is an object of the present invention to provide a dishwasher of which washability is enhanced.

It is another object of the present invention to provide a dishwasher of which washability is enhanced without increasing an amount of water used.

To achieve the objects of the present invention, the present invention provides a dishwasher including a sump for holding cleaning water, a cleaning pump for pumping the cleaning water from the sump, a spray arm for spraying the cleaning water through two or more nozzles, a supply flow passage for forming a flow passage to supply the cleaning water pumped by the cleaning pump to the spray arm, and an air mixing unit for drawing external air to spray the cleaning water through the nozzles together with the air.

In one embodiment of the present invention, the air mixing unit may be mounted between the nozzle which sprays the cleaning water and a connection portion which connects the spray arm to the supply flow passage to introduce the cleaning water to the spray arm.

In one embodiment of the present invention, the air mixing unit may be mounted between the nozzle closest to the connection portion and the connection portion.

In one embodiment of the present invention, the air mixing unit may include an air introduction hole formed in a direction different from a direction in which the nozzle sprays the cleaning water. And, the air mixing unit may include the air introduction hole formed toward a rotation direction of the spray arm. Or, the air mixing unit may include the air introduction hole formed in an upper side or an underside thereof perpendicular to the rotation direction of the spray arm.

In one embodiment of the present invention, a number and a size of the air introduction hole may be determined based on a cross sectional area of the nozzles.

In one embodiment of the present invention, the air mixing unit may be mounted to an end of the supply flow passage connected to the spray arm.

In one embodiment of the present invention, the air mixing unit may be mounted to a portion closest to the connection portion of the spray arm among portions of the supply flow passage through which the cleaning water flows in a vertical direction, or the air mixing unit may be mounted to a portion closest to the connection portion of the spray arm among portions of the supply flow passage through which the cleaning water flows in a horizontal direction.

In one embodiment of the present invention, the air mixing unit may include an air introduction hole for introduction of the air from an outside of the tube, a compression tube having a cross sectional area reduced in a flow direction of the cleaning water, an air suction hole for serving as a suction passage of the air introduced through the air introduction hole thus into an inside of the tube, and a buffer portion for buffering a pressure difference between the inside of the tube and the outside of the tube.

In one embodiment of the present invention, the air mixing unit may include two or more suction holes formed in symmetry.

In one embodiment of the present invention, the air suction hole may be formed at an end portion of the compression tube with reference to a direction the cleaning water flows.

In one embodiment of the present invention, the buffering portion has a donut shape surrounding the cross sectional area reducing portion of the compression tube.

In one embodiment of the present invention, the air introduction hole and the air suction hole are not arranged on a line in a radial direction with reference to an axis of the tube.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:

FIG. 1 is a section illustrating a general dishwasher.

FIG. 2 is a section illustrating an air mixing unit applied to the present invention.

FIG. 3 is schematic view illustrating an example of an air mixing unit mounted to a spray arm in accordance with an embodiment of the present invention.

FIG. 4 is schematic view illustrating an example of an air mixing unit mounted to an end of a supply flow passage in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In what follows, a dishwasher according to preferred embodiments of the present invention will be described in detail with reference to the appended drawings.

FIG. 1 is a section illustrating a general dishwasher, referring to which a basic structure of the dishwasher will be described, at first.

Referring to FIG. 1, the dishwasher 1 may include a cabinet 10 which forms an exterior appearance of the dishwasher 1, a tub 115 in the cabinet 10 to provide a cleaning space, a rack 20 arranged to move in/out of the tub 115 for placing tableware therein, a spray arm 30 mounted in the tub 115 for spraying the cleaning water toward the rack to clean the tableware, a cleaning water supply unit 40 connected to the spray arm 30 for supplying the cleaning water, a sump 50 for holding the cleaning water, and a filter unit 60 for filtering the cleaning water.

The cabinet 10 may have a door 111 for a user to open/close the cleaning space, and a control panel (not shown) for user's selection of operation of the dishwasher.

The sump 50 under the tub 115 for holding the cleaning water therein is connected to a water supply unit 151 and a water drain unit 155, wherein the water supply unit 151 may include a water supply hose connected between an external utility water supply source (Not shown) and the sump 50 for supplying the cleaning water to the sump 50. The sump 50 may have a heater (not shown) provided thereto additionally, for heating the cleaning water.

The drain unit 155 may include a drain pump 156, a drain hose 157, and a drain chamber 158 connected to the sump 50, for draining the cleaning water from the sump 50 to an outside of the dishwasher 1. The drain pump 156 in the drain chamber 158 has one side connected to the sump 50 through the drain chamber 158, and the other side connected to the drain hose 157 for draining the cleaning water from the sump 50 to an outside of the dishwasher 1 through the drain hose 157.

The rack 20 includes two or more than two racks, such as an upper rack and a lower rack, to provide spaces for placing the tableware therein, wherein each of the racks may have a plurality of wheels (not shown) for easy push in/pull out the rack to/from the cleaning space in the tub 115 through the door 111 opened, and the tub 115 may have rails (Not shown) for supporting the wheels, additionally.

The spray arm 30 connected to the sump 50 through the cleaning water supply unit 40 may include only one, or both of, an upper arm 131 for spraying the cleaning water from above the rack 20 and a lower arm 132 for spraying the cleaning water from under the rack 20. If the rack 20 is two or more than two, a top arm (not shown) may be further included for spraying the cleaning water from above the upper rack, and the upper arm 131 may be mounted between the upper rack and the lower rack. The spray arm 30 has two or more than two nozzles 135 arranged in symmetry for ejecting the cleaning water, and the spray arms 30 can be rotated by the spray pressure from the nozzles 135.

The cleaning water supply unit 40 may include a supply flow passage (Or, a water guide) 141 and a pump 145 for supplying the cleaning water from the sump 50 to the upper and lower arms 131 and 132. The upper arm 131 and the lower arm 132 are connected to the pump 145 through the supply flow passage 141, and the pump 145 pressurizes the cleaning water in the sump 50 to supply the cleaning water to the upper and lower arms 131 and 132.

Though the supply flow passage 141 may have two independent flow passages connected to the upper arm 131 and the lower arm 132 respectively, or may have one flow passage as shown in FIG. 1 branched and connected to the upper arm 131 and the lower arm 132, respectively. In a latter case, the supply flow passage 141 may further include a change-over valve 146 at a branch point thereof for supplying the cleaning water to the upper arm 131 and the lower arm 132, selectively.

The cleaning water pressurized by the pump 145 thus may be supplied either the upper arm 131 or the lower arm 132 through the change-over valve 146 or both of the upper arm 131 and the lower arm 132 at the same time.

A portion of the supply flow passage 141 for supplying the cleaning water to the upper arm 131 may be extended upward from a lower side of the tub 115 along an inside circumference of the tub 115 on a rear side of the cleaning space, bent toward a center of the cleaning space, and connected to a middle portion of the upper arm 131.

The filter unit 60 may include a chamber 161 for introduction of the cleaning water thereto, a filter 162 on a top side of the chamber 161 for filtering dirt, a dirt discharge portion 163 connected between the chamber 161 and the drain unit 155, and a collection hole 164 for collecting the cleaning water sprayed from the spray arm 30 and flowing on a bottom of the cleaning space. In this case, the supply flow passage 141 may further include a filtering flow passage 147 connected to the chamber 161.

The cleaning water circulates as follows. The cleaning water from the utility water supply source is introduced to the sump 50 through the water supply unit 151, and, if a certain amount of the cleaning water is introduced to the sump 50, an impeller (not shown) in the pump 145 rotates to draw in the cleaning water, and supply the cleaning water to the upper arm 131 and the lower arm 132 through the supply flow passage 141 at the same time or selectively.

The cleaning water being supplied to the spray arm 30 is sprayed to insides of the cleaning spaces through the two or more than two nozzles 135 to clean the tableware placed in the rack 20, wherein the upper arm 131 having the nozzles 135 formed to face downward sprays the cleaning water downward, and the lower arm 132 having the nozzles 135 formed to face upward sprays the cleaning water upward. The cleaning water sprayed through the nozzles 135 is collected at the sump 50 through the collection hole 164.

A portion of the cleaning water being supplied to the upper arm 131 and the lower arm 132 through the supply flow passage 145 is supplied to the chamber 161 of the filter unit 60 through the filtering flow passage 147. Though the cleaning water supplied to the chamber 161 is collected to the sump 50 through the collection hole 164 after escaping the filter 162 on the upper side of the chamber 161, the dirt contained in the cleaning water can not pass the filter 162, but is remained in the chamber 161, and may be broken into small pieces by a disposer.

The dirt held in the chamber 161 may be discharged together with the cleaning water when the cleaning water is drained from the sump 60. The drain chamber 158 provided to the drain pump 156 is connected, not only to the sump 50 through a check valve 159, but also to the chamber 161 through the dirt discharge portion 163.

The check valve 159 allows the cleaning water to move from the sump 50 to the drain chamber 158 only, but not to an opposite direction. If the drain pump 156 is put into operation, the cleaning water is drained to an outside of the dishwasher 1 from the sump 50 through the check valve 159, the drain pump 156, and the drain hose 157.

Moreover, a negative pressure occurred in the drain chamber 156 upon putting the drain pump 156 into operation discharges the dirt from the chamber 161 of the filter unit 60 to the drain chamber 157 through the dirt discharge portion 163, and, therefrom, to an outside of the dishwasher 1, together with the cleaning water.

As described in the background of the invention, in order to increase the washability without increasing the temperature of the cleaning water or increasing the amount of the water used, it is required to increase the spray pressure of the cleaning water ejected through the nozzle, and, moreover, a method is required for increasing the spray pressure without increasing the rotation speed of the motor of the pump 145 which pressurizes the cleaning water in the sump 50 to supply the cleaning water to the upper and lower arms 131 and 132.

The present invention provides a dishwasher which increases the spray pressure of the cleaning water ejected from the nozzles by mixing the cleaning water with air so that the washability can be enhanced, not with increasing the amount of the water used, but with a fixed amount of the water used.

Under an assumption that the washability will be the same if the spray pressures of the cleaning water are the same and cleaning time periods are the same, the present invention permits to obtain the same or a higher washability while reducing the flow rate of the water used as much as a flow rate of the air being drawn into the cleaning water.

As a method for making the water to draw the air, the Venturi effect may be used, which is an effect of a venturi tube that is a short tube having a reduced cross sectional area on a fluid flow. Since a flow speed of the fluid becomes faster (The continuity equation) when the fluid flows through the venturi tub having the reduced cross sectional area, and, if the flow speed increases, since a water pressure drops (Bernoulli equation), the air can be drawn through a hole made in a portion the water pressure is dropped.

FIG. 2 is a section illustrating an air mixing unit applied to the present invention.

The air mixing unit 70 may include a compression tube 171 having a partial reduction of a cross sectional area in a flow direction of the cleaning water, an air suction hole 172 for serving as a suction passage of the air into an inside of the tube by a pressure dropped owing to the venturi effect, an air introduction hole 173 opened to an outside of the tube for serving as a passage of air introduction, and a buffer portion 174 for buffering a pressure difference between the inside of the tube and the outside of the tube.

The air suction hole 172 is formed in the compression tube 171 at an end portion of the portion the cross sectional area is reduced with reference to the flow direction of the cleaning water. In order to make the air drawn thus be mixed with the cleaning water passing at a fast speed, two or more than two air suction holes 172 may be formed, symmetrically (Point symmetry, or line symmetry).

As shown in a right side drawing (A cross section perpendicular to a direction the cleaning water flows) in FIG. 2, the buffering portion 174 has a donut shape which surrounds the portion of the reduced cross sectional area for preventing the cleaning water being discharging through the air suction hole 172 from escaping to an outside of the compression tube 171 to hold remaining water therein, and controlling a pressure of the air being drawn through the air suction hole 172.

In order to prevent the cleaning water being discharging to the buffering portion 174 through the air suction hole 172 from escaping to an outside of the compression tube 171 through the air introduction hole 173, positions of the air suction holes 172 and the air introduction holes 173 may be formed not to be arranged on a line with each other in a radial direction with reference to an axis of the tube.

In the present invention, the air mixing unit 70 which utilizes the venturi effect is mounted between the sump 50 which supplies the cleaning water, and the nozzle 135 which sprays the cleaning water for increasing the spray pressure of the cleaning water sprayed through the nozzle 135 even if a small amount is used, wherein it may be favorable to mount the air mixing unit 70 at a position close to the nozzle 135 through which the cleaning water is ejected moved away from the tube through which the cleaning water is passing.

A number of the air introduction holes 173 and/or a size (A cross sectional area) thereof in the air mixing unit 70 may be determined with reference to a cross sectional area of the nozzle 135 which ejects the water, and the reduced cross sectional area of the compression tube 171 may also be a factor for determining the number of the air introduction holes 173 and/or a size (A cross sectional area) thereof.

FIG. 3 is schematic view illustrating an example of an air mixing unit mounted to a spray arm in accordance with an embodiment of the present invention.

The symmetric spray arm 30 is connected to an end of the supply flow passage 141 with a connection portion 136 at a center portion of the spray arm 30, and has a plurality of the nozzles 135 on both sides thereof for spraying the cleaning water to the cleaning space uniformly while the spray arm 30 is rotating round the connection portion 136 by the pressure generated when the cleaning water is sprayed through the nozzles 135 supplied thereto through the supply flow passage 141.

Though the air mixing unit 70 of the present invention may be arranged between the connection portion 136 of the spray arm 30 and the nozzle 135, it is favorable to mount the air mixing unit 70 between the nozzle 135 which is the closet to the center of the spray arm 30 and the connection portion 136. If the air mixing unit is mounted close to an end of the spray arm away from the center of the spray arm, mass of the spray arm to be rotated becomes large due weight of the air mixing unit to require a spray pressure higher than before for rotating the spray arm, resulting in a low rotation speed of the spray arm even if the cleaning water is ejected from the cleaning water at the same spray pressure, thereby making the washability poor.

The nozzle 135 is formed in the spray arm 30 tilted to one side for rotating the spray arm 30 and ejects the cleaning water, wherein the spray arm 30 rotates in a direction opposite to a horizontal component of a direction in which the nozzle 135 ejects the cleaning water.

If the air mixing unit 70 is mounted between the connection portion 136 of the spray arm 30 and the nozzle 135, the position of the air introduction hole 173 which is a passage for introducing the air from an outside to an inside of the tube may be determined taking the direction (Or, the rotation direction of the spray arm) in which the nozzle 135 ejects the cleaning water into account.

Since the air is introduced to an inside of the spray arm 30 from an inside of the tub 115 through the air introduction hole 173 of the air mixing unit 70, a pressure in the vicinity of the air introduction hole 173 may be low, relatively. If the air introduction hole 173 is formed in a direction in which the nozzle 135 ejects the cleaning water, or in a rear side of the direction of rotation of the spray arm 30, to drop a pressure on the rear side of the rotation of the spray arm 30, the direction of the air introduction hole 173 is liable to interfere with the rotation of the spray arm 30.

Therefore, it may be favorable to form the air introduction hole 173 in a direction different from the direction of ejection of the cleaning water from the nozzle 135, for an example, the rotation direction of the spray arm 30, or in an upper side on or in an underside of the spray arm 30 perpendicular to the rotation direction of the spray arm 30.

Referring to FIG. 3, since a distance to an outer side of the spray arm 30 from the tube of the spray arm 30 the cleaning water passes therethrough is far in the rotation direction of the spray arm 30, which makes it difficult to form the air introduction hole 173 in the rotation direction of the spray arm 30, the air introduction hole 173 is formed in the underside of the spray arm 30 perpendicular to the rotation direction of the spray arm 30.

FIG. 4 is schematic view illustrating an example of an air mixing unit mounted to an end of a supply flow passage in accordance with another embodiment of the present invention.

Referring to FIG. 4, the air mixing unit 70 is mounted to an end of the supply flow passage which is connected to the connection portion 136 of the spray arm 30 so that the cleaning water mixed with the air at the air mixing unit 70 passes through the connection portion 136, is divided into two sides and ejected through the nozzle 135. Different from the embodiment shown in FIG. 3, the embodiment shown in FIG. 4 suggests mounting the air mixing unit 70, not to a movable member, but a stationary member, making the position of the air introduction hole 173 not to influence to the spray pressure of the cleaning water, significantly.

The supply flow passage 141 is formed extended from a lower side to an upper side of the tub 115 along an inside circumference of the tub 115 in a rear side of the washing space and, therefrom, bent toward the center of the cleaning space, extended to the middle of the upper arm 131, and bent at 90 degrees finally so as to be coupled to the connection portion 136 of the upper arm 131 for supplying the cleaning water to upward from the sump 50 which is placed on a lower side of the dishwasher for storing the cleaning water.

If a distance between the upper arm 131 and the portion of the supply flow passage 141 extended toward the center of the cleaning space from the inside circumference of the tub 115 on the rear side of the cleaning space is adequate, the air mixing unit 70 may be mounted to an end of the supply flow passage 141 just over the connection portion 136 of the upper arm 131 (A portions closest to the connection portion 136 of the upper arm 131 among portions through which the cleaning water flows in a vertical direction of the supply flow passage 141), otherwise, the air mixing unit 70 may be mounted to an end of a portion of the supply flow passage 141 extended toward the center of the cleaning space from the inside circumference of the tub 115 in the rear side of the cleaning space, i.e., a position just before the supply flow passage is bent at 90 degrees finally to couple to the connection portion 136 (A position closest to the connection portion 136 of the upper arm 131 in a portion the cleaning water flows in a horizontal direction of the supply flow passage 141).

As has been described, the dishwasher of the present invention has the following advantages.

The washability of the dishwasher can be enhanced, not with increasing the amount of water used, but with reducing the amount of water used.

Moreover, the amount of water used can be reduced while maintaining the spray pressure similar to the related art, and heating energy and heating time period can be reduced for elevating the temperature of the cleaning water.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A dishwasher comprising: a sump for holding cleaning water; a cleaning pump for pumping the cleaning water from the sump; a spray arm for spraying the cleaning water through two or more nozzles; a supply flow passage for forming a flow passage to supply the cleaning water pumped by the cleaning pump to the spray arm; and an air mixing unit for drawing external air to spray the cleaning water through the nozzles together with the air.
 2. The dishwasher as claimed in claim 1, wherein the air mixing unit is mounted between the nozzle which sprays the cleaning water and a connection portion which connects the spray arm to the supply flow passage to introduce the cleaning water to the spray arm.
 3. The dishwasher as claimed in claim 2, wherein the air mixing unit is mounted between the nozzle closest to the connection portion and the connection portion.
 4. The dishwasher as claimed in claim 2, wherein the air mixing unit includes an air introduction hole formed in a direction different from a direction in which the nozzle sprays the cleaning water.
 5. The dishwasher as claimed in claim 4, wherein the air mixing unit includes the air introduction hole formed toward a rotation direction of the spray arm.
 6. The dishwasher as claimed in claim 4, wherein the air mixing unit includes the air introduction hole formed in an upper side or an underside thereof perpendicular to the rotation direction of the spray arm.
 7. The dishwasher as claimed in claim 4, wherein a number and a size of the air introduction hole are determined based on a cross sectional area of the nozzles.
 8. The dishwasher as claimed in claim 1, wherein the air mixing unit is mounted to an end of the supply flow passage connected to the spray arm.
 9. The dishwasher as claimed in claim 8, wherein the air mixing unit is mounted to a portion closest to the connection portion of the spray arm among portions of the supply flow passage through which the cleaning water flows in a vertical direction.
 10. The dishwasher as claimed in claim 8, wherein the air mixing unit is mounted to a portion closest to the connection portion of the spray arm among portions of the supply flow passage through which the cleaning water flows in a horizontal direction.
 11. The dishwasher as claimed in claim 1, wherein the air mixing unit includes; an air introduction hole for introduction of the air from an outside of the tube, a compression tube having a cross sectional area reduced in a flow direction of the cleaning water, an air suction hole for serving as a suction passage of the air introduced through the air introduction hole thus into an inside of the tube, and a buffer portion for buffering a pressure difference between the inside of the tube and the outside of the tube.
 12. The dishwasher as claimed in claim 11, wherein the air mixing unit includes two or more suction holes formed in symmetry.
 13. The dishwasher as claimed in claim 11, wherein the air suction hole is formed at an end portion of the compression tube with reference to a direction the cleaning water flows.
 14. The dishwasher as claimed in claim 11, wherein the buffering portion has a donut shape surrounding the cross sectional area reducing portion of the compression tube.
 15. The dishwasher as claimed in claim 11, wherein the air introduction hole and the air suction hole are not arranged on a line in a radial direction with reference to an axis of the tube. 